Those smart advertising people at Canadian ad agency Leo Burnett [Flash] came up with this clever art/public service/marketing of Campbell's Soup installation that tugged on your heart string:

In a grocery store 4,820 cans of Campbell's Soup were used to build an installation piece that spelled HUNGER. Signage beside the piece encouraged shoppers to buy one and donate it to their local food bank. As shoppers bought cans from the display the word HUNGER slowly disappeared. This allowed people to see how their individual effort coule help bring an end to the problem of hunger.

Food banks wouldn't mind having the same kind of each can lol. Tomatoes are the cheapest actually (in my local grocery store). My class collected money and bought $100 worth of canned tomatoes and the rest of the class brought in diapers, other canned goods and we collected 3200 cans in the 3 week duration.